Silyl-functional linear prepolymers, production and use thereof

Abstract

The invention relates to coatings with a contact angle hysteresis in water as measured by the tilting plate method of at most 20° made from silyl-terminated linear prepolymers which may cross-link with the surface of the substrate for coating, wherein the silyl-terminated linear prepolymers may be obtained by reaction of compounds of general formula (I): X-A-X′ (I), where A=a polyoxyalkylene chain of ethylene oxide units or ethylene oxide and propylene oxide units with a maximum fraction of 50 wt. % of propylene oxide units based on the weight of A, X═OH, NH 2 , NHR, NR 2 or OR, wherein R independently=a linear or branched 1-10 C alkyl, a 6-10 C alkaryl or aralkyl or a 5-10 C aryl and the compound of general formula (I) has a number average molecular weight of at least 100 g/mol, with compounds of general formula (II) Y—B—Si(OR 1 ) r (R 2 ) 3−r , where Y=a group reactive with OH, NH 2 , NHR and/or NR 2 , B=a chemical bond or a divalent low-molecular weight organic group with preferably 1-50 carbon atoms, OR 1 =a hydrolysable group, R 2 =a linear or branched 1-6C alkyl and r=a number from 1 to 3 and optionally unreacted hydrogen atoms on the group X and/or the group X′ are optionally alkylated. The invention further relates to the production of such coatings and the use of the silyl-terminated linear pre-polymers from production of such coatings and application in mixtures with stellate silylated prepolymers.

1 . Method of preparing coatings comprising:
 obtaining silyl-terminated linear prepolymers by reacting compounds of general formula (I)—
   X-A-X′  (I) 
   
       wherein A is a polyoxyalkylene chain of ethylene oxide units or ethylene oxide and propylene oxide units containing a maximum fraction of 50 wt. % of propylene oxide units based on the weight of A; X is OH, NH 2 , NHR, NR 2  or OR, wherein the R groups independently of each other stand for a linear or branched alkyl group containing 1 to 10 carbon atoms, an alkaryl or aralkyl group containing 6 to 10 carbon atoms or an aryl group containing 5 to 10 carbon atoms; X′ is OH, NH 2 , NHR or NR 2 , wherein the R groups are independently a linear or branched alkyl group containing 1 to 10 carbon atoms, an alkaryl or aralkyl group containing 6 to 10 carbon atoms or an aryl group containing 5 to 10 carbon atoms; and
 wherein the compound of general formula (I) has a number average molecular weight of at least 100 g/mol, 
 with compounds of general formula (II)
   Y—B—Si(OR 1 ) r (R 2 ) 3−r   (II) 
 
 
       wherein Y is a group that is reactive towards OH, NH 2 , NHR and/or NR 2 ; B is a chemical bond or a divalent, low molecular weight organic group containing 1 to 50 carbon atoms;
 OR 1  is a hydrolyzable group; R 2  is a linear or branched alkyl group containing 1 to 6 carbon atoms; and r is a number from 1 to 3; where appropriate, unreacted hydrogen atoms on the group X and/or the group X are optionally alkylated, and 
 adding the silyl-terminated linear prepolymers to a coatings mixture, 
 wherein the coatings have a contact angle hysteresis with water as measured by the tilting plate method of at most 20°, and 
 wherein the silyl-terminated linear prepolymers can cross-link with each other and with the surface of the substrate to be coated. 
 
     
     
         2 . Method according to  claim 1  wherein Y is NCO, a carboxylic acid anhydride group, a carboxylic acid chloride group, an acrylate group, an aldehyde group, an epoxy group or a haloalkyl group, and B is a divalent organic group containing 1 to 50 carbon atoms. 
     
     
         3 . Method according to  claim 1  wherein the compound of formula (I) is a dihydroxy terminated polyoxyalkylene diol, a diamino terminated polyoxyalkylene diamine, a monohydroxy-monoamine terminated polyoxyalkylene monol monoamine, a monohydroxy-monoalkoxy terminated polyoxyalkylene monol or a monoamino monoalkoxy terminated polyoxyalkylene monoamine. 
     
     
         4 . Method according to  claim 1  wherein A is a polyoxyalkylene chain of ethylene oxide and propylene oxide units having a maximum fraction of 40 wt. % propylene oxide units, based on weight of A. 
     
     
         5 . Method according to  claim 1  wherein the static water contact angle as determined by the sessile drop method is at most 70°. 
     
     
         6 . Method according to  claim 1  wherein the contact angle hysteresis with water as measured by the tilting plate method is at most 15°. 
     
     
         7 . Method according to  claim 1  wherein the OR 1  group is an alkoxy group and r=1, 2 or 3. 
     
     
         8 . Method according to  claim 1  further comprising reacting OH and/or NH 2  groups that have neither reacted with the compound of Formula (II) nor been alkylated with compounds possessing a functional group reactive towards OH and/or NH 2  groups and having another reactive group chosen from isocyanate groups, (meth)acrylate groups, oxirane groups, alcoholic OH groups, primary and secondary amino groups, thiol groups and silane groups. 
     
     
         9 . Method according to  claim 1  wherein the number average molecular weight of the compound of Formula (I) is 100 to 50 000 g/mol. 
     
     
         10 . Method according to  claim 1  further comprising one or more entities chosen from biologically active substances, pigments, colorants, fillers, silica units, nanoparticles, organofunctional silanes, biological cells, receptors or receptor-carrying molecules or cells that are physically embedded and/or covalently bonded to or in these. 
     
     
         11 . Method according to  claim 1  wherein the coatings comprise no additional self-crosslinking polymers. 
     
     
         12 . Method according to  claim 1  wherein the coatings comprise no additional externally crosslinking polymers. 
     
     
         13 . Method according to  claim 1  wherein the coatings further comprise monomeric silanes. 
     
     
         14 . Method according to  claim 1  wherein the coatings further comprise silyl-terminated polymers different from those produced according to the reaction in  claim 1 . 
     
     
         15 . Method according to  claim 1  further comprising obtaining additional silyl-terminated polymers by reacting star-shaped compounds of general formula (III)—
   (X-A) m -Z-(A-X′) n   (III)   
       wherein Z is an organo-chemical central unit that determines the number of arms of the star-shaped compound; A is a polyoxyalkylene chain of ethylene oxide units or ethylene oxide and propylene oxide units containing a maximum fraction of 50 wt. % of propylene oxide units based on weight of A; X is OH, NH 2 , NHR, NR 2  or OR, wherein the R groups are independently a linear or branched alkyl group containing 1 to 10 carbon atoms, an alkaryl or aralkyl group containing 6 to 10 carbon atoms or an aryl group containing 5 to 10 carbon atoms; X′ is OH, NH 2 , NHR or NR 2 , wherein the R groups are independently a linear or branched alkyl group containing 1 to 10 carbon atoms, an alkaryl or aralkyl group containing 6 to 10 carbon atoms or an aryl group containing 5 to 10 carbon atoms; the sum of n and m is a whole number≧3, wherein n is ≧1; and
 the compound of general formula (III) has a number average molecular weight of at least 1000 g/mol, 
 with compounds of general formula (IV)—
   Y—B—Si(OR 1 ) r (R 2 ) 3−r   (IV) 
 
 
       wherein Y is a group that is reactive towards OH, NH 2 , NHR and/or NR 2 ; B is a chemical bond or for a divalent, low molecular weight organic group containing preferably 1 to 50 carbon atoms; OR 1  is a hydrolyzable group; R 2  is a linear or branched alkyl group containing 1 to 6 carbon atoms; and r is a number from 1 to 3; and
 wherein appropriate, unreacted hydrogen atoms on the group X and/or the group X′ are optionally alkylated. 
 
     
     
         16 . Method according to  claim 1  further comprising depositing the coatings mixture onto a substrate to be coated, wherein there occurs before deposition, simultaneously with deposition or subsequently after deposition an at least partial crosslinking reaction between the silyl end groups and optionally present reactive groups of ends that do not carry silyl end groups and/or the substrate. 
     
     
         17 . Method according to  claim 16  wherein before, during and/or after having deposited the coatings mixture containing the silyl terminated linear prepolymer onto the substrate to be coated, one or more entities chosen from biologically active substances, pigments, colorants, fillers, silica units, nanoparticles, organofunctional silanes, biological cells, receptors or receptor-carrying molecules or cells or precursors of the entities, are brought into contact with the silyl terminated linear prepolymer. 
     
     
         18 . Method according to  claim 15  wherein before, during and/or after depositing the coatings mixture containing the silyl terminated linear prepolymer onto the substrate to be coated, one or more entities chosen from biologically active substances, pigments, colorants, fillers, silica units, nanoparticles, organofunctional silanes, biological cells, receptors or receptor-carrying molecules or cells or precursors of the entities, are brought into contact with the silyl terminated linear prepolymer and/or the star-shaped silyl terminated prepolymer. 
     
     
         19 . Method according to  claim 16  wherein the coating thickness after the crosslinking reaction is 1 mm or less. 
     
     
         20 . Coatings mixture comprising:
 (A) at least one silyl-terminated linear prepolymer obtained by reacting compounds of general formula (I)
   X-A-X′  (I) 
   
       wherein A is a polyoxyalkylene chain of ethylene oxide units or ethylene oxide and propylene oxide units containing a maximum fraction of 50 wt. % of propylene oxide units based on weight of A; X is OH, NH 2 , NHR, NR 2  or OR, wherein the R groups are independently a linear or branched alkyl group containing 1 to 10 carbon atoms, an alkaryl or aralkyl group containing 6 to 10 carbon atoms, or an aryl group containing 5 to 10 carbon atoms; X′ is OH, NH 2 , NHR or NR 2 , wherein the R groups are independently a linear or branched alkyl group containing 1 to 10 carbon atoms, an alkaryl or aralkyl group containing 6 to 10 carbon atoms, or an aryl group containing 5 to 10 carbon atoms, and
 wherein the compound of the general formula (I) has a number average molecular weight of at least 100 g/mol, 
 with compounds of general formula (II)
   Y—B—Si(OR 1 ) r (R 2 ) 3−r   (II) 
 
 
       wherein Y is a group that is reactive towards OH, NH 2 , NHR and/or NR 2 ; B is a chemical bond or for a divalent, low molecular weight organic group containing preferably 1 to 50 carbon atoms; OR 1  is a hydrolyzable group; R 2  is a linear or branched alkyl group containing 1 to 6 carbon atoms; and r is a number from 1 to 3; and,
 wherein appropriate, unreacted hydrogen atoms on the group X and/or the group X′ are optionally alkylated, and 
 (B) at least one silyl-terminated star-shaped prepolymer that can be obtained by reacting a star-shaped compound of the general formula (III):
   (X-A) m -Z-(A-X′) n   (III) 
 
 
       wherein Z is an organo-chemical central unit that determines the number of arms of the star-shaped compound; A, X and X have the same meanings as in component (A) but are independent of these; and the sum of n and m is a whole number≧3, wherein n is ≧1; and
 wherein the compound of the general formula (III) has a number average molecular weight of at least 1000 g/mol, 
 with compounds of general formula (IV)
   Y—B—Si(OR 1 ) r (R 2 ) 3−r   (IV) 
 
 
       wherein Y, B, OR 1 , R 2  and r have the same meanings as in component (A) but are independent of these, and
 where appropriate, unreacted hydrogen atoms on the group X and/or the group X′ are optionally alkylated. 
 
     
     
         21 . Anti-soiling agents, cleaning agents and washing agents for hard and soft surfaces, hair care agents, fabric treatment agents, wall, cladding and grouting agents, agents for the treatment of vehicles, agents for the internal and external coating of containers, bioreactors and heat exchangers comprising silyl-terminated linear prepolymers prepared according to  claim 1 .